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A Stimulating Treatment for Drug Addiction

Drug addiction is notoriously difficult to treat. Limited treatment options are available for those suffering from addiction, including behavioral therapy, rehabilitation programs, and medication. However, current drug addiction medications are only approved to treat opioid, tobacco, or alcohol abuse, leaving out many other drugs of abuse,such as cocaine or methamphetamine.

Yet even when patients successfully complete rehab or stick to a medication plan, there is still a risk of relapse. This can often be due to the emergence of drug cravings. For instance, a former alcoholic may see a sign for a bar they used to frequent. That sign can induce feelings of craving for alcohol, even long after the user quits or abstains from drinking. Strong cravings could lead to a relapse and a resumption of the cycle of addiction.

No pharmaceutical treatments are currently available for cocaine addiction.

However, a recent discovery may change the way we approach drug addiction treatment. Italian researchers, working alongside the National Institute on Drug Abuse (NIDA), were able to reduce drug cravings and usage in cocaine addicts for the first time using a technique called transcranial magnetic stimulation (TMS).

Long-term use of drugs change how brain cells communicate to each other. Think of a drug addict’s brain cells as speaking in gibberish, or unable to speak at all. Important messages aren’t being sent correctly, which contributes to the negative effects of addiction.

In a TMS procedure, researchers place a figure-8-shaped magnetic coil on the patient’s head. When turned on, the coil can send electrical signals into the brain. Importantly, brain cells communicate using electricity, and the “messages” between cells depend on the strength and frequency of these signals. Researchers found that the electrical signals from TMS help change the way brain cells “speak” to each other, getting rid of the gibberish and making cells communicate normally.

TMS uses a magnetic coil to send electric signals into the brain.

In the case of drug addicts, the electrical signals from the magnetic coil are focused at a brain region called the dorsolateral prefrontal cortex (dlPFC). This is a part of the brain that handles decision making and cognitive ability, and is affected by drugs of abuse. For instance, drug addicts demonstrate lower dlPFC activity compared to non-addicted individuals during cognitive tasks.

Knowing how important this brain region is, researchers performed a study where they stimulated the dlPFC of drug addicts using TMS. They had cocaine addicts undergo either the TMS procedure or take medication (as a control group). They found that the cocaine users who experienced TMS had less cocaine cravings than their control counterparts. Further, the TMS group had more cocaine-free urine samples compared to the control group.

The dorsolateral prefrontal cortex is affected by drug addiction.

Other studies support these results, focusing specifically on the prefrontal cortex, which appears to be a “sweet spot” for treating drug addiction. For instance, an earlier study found that daily TMS sessions, focused more broadly at the left prefrontal cortex, reduced cocaine craving. A later study honing in on the left dlPFC found similar reduction of craving in cocaine users.

Interestingly, the Italian TMS study was based on a rodent experiment with a very similar design. In this study, researchers allowed rats to develop a cocaine addiction and then stimulated a brain region analogous to the human dlPFC. Amazingly, the rats decreased cocaine seeking behaviors, much like their human counterparts in the TMS study. When this brain region was inhibited, or “turned off”, the rats increased their cocaine seeking.

Despite their promise, these TMS studies are just the beginning. Researchers are still a long way from developing a cure or reliable treatment for drug addiction. Like any new drug or treatment, it will be many years before TMS could be accepted as standard care for drug addicts. However, TMS has been successfully used to help patients in other ways. For instance, it has been used to help treat depression and is often used to help doctors identify damage from strokes, brain injuries, and neurodegenerative diseases. TMS holds a lot of promise and is on the cusp of being a successful drug addiction treatment. It’s only a matter of time before this stimulating idea becomes reality.

About Deirdre Sackett

Deirdre Sackett is a 4th year graduate student in the Behavioral Neuroscience department at UNC. She researches dopamine dynamics during decision making behavior in the Carelli lab. Outside the lab, Deirdre is actively involved in science communication and outreach. She is the current Vice President and Chief Editor of SWAC.